Index: include/llvm/IR/IntrinsicsX86.td
===================================================================
--- include/llvm/IR/IntrinsicsX86.td
+++ include/llvm/IR/IntrinsicsX86.td
@@ -8709,3 +8709,13 @@
   def int_x86_sha256msg2 : GCCBuiltin<"__builtin_ia32_sha256msg2">,
       Intrinsic<[llvm_v4i32_ty], [llvm_v4i32_ty, llvm_v4i32_ty], [IntrNoMem]>;
 }
+
+//===----------------------------------------------------------------------===//
+// Bit Scan intrinsics
+let TargetPrefix = "x86" in {
+  def int_x86_bit_scan_forward : GCCBuiltin<"__builtin_ia32_bit_scan_forward">,
+      Intrinsic<[llvm_i32_ty], [llvm_i32_ty], [IntrNoMem]>;
+	  
+  def int_x86_bit_scan_reverse : GCCBuiltin<"__builtin_ia32_bit_scan_reverse">,
+      Intrinsic<[llvm_i32_ty], [llvm_i32_ty], [IntrNoMem]>;
+}
Index: lib/Target/X86/X86IntrinsicsInfo.h
===================================================================
--- lib/Target/X86/X86IntrinsicsInfo.h
+++ lib/Target/X86/X86IntrinsicsInfo.h
@@ -2152,6 +2152,8 @@
                      X86ISD::SCALAR_FP_TO_UINT_RND, 0),
   X86_INTRINSIC_DATA(avx512_vcvtss2usi64, INTR_TYPE_2OP,
                      X86ISD::SCALAR_FP_TO_UINT_RND, 0),
+  X86_INTRINSIC_DATA(bit_scan_forward,  INTR_TYPE_1OP, X86ISD::BSF, 0),
+  X86_INTRINSIC_DATA(bit_scan_reverse,  INTR_TYPE_1OP, X86ISD::BSR, 0),
   X86_INTRINSIC_DATA(fma_vfmadd_pd,        INTR_TYPE_3OP, X86ISD::FMADD, 0),
   X86_INTRINSIC_DATA(fma_vfmadd_pd_256,    INTR_TYPE_3OP, X86ISD::FMADD, 0),
   X86_INTRINSIC_DATA(fma_vfmadd_ps,        INTR_TYPE_3OP, X86ISD::FMADD, 0),
Index: test/CodeGen/X86/bitscan.ll
===================================================================
--- test/CodeGen/X86/bitscan.ll
+++ test/CodeGen/X86/bitscan.ll
@@ -0,0 +1,17 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mcpu=corei7 | FileCheck %s
+declare i32 @llvm.x86.bit.scan.forward(i32 %val)
+declare i32 @llvm.x86.bit.scan.reverse(i32 %val)
+
+define i32 @test_bsf(i32 %val) {
+  %call = call i32 @llvm.x86.bit.scan.forward(i32 %val)
+  ret i32 %call
+; CHECK-LABEL: test_bsf
+; CHECK: bsfl    %edi, %eax
+}
+
+define i32 @test_bsr(i32 %val) {
+  %call = call i32 @llvm.x86.bit.scan.reverse(i32 %val)
+  ret i32 %call
+; CHECK-LABEL: test_bsr
+; CHECK: bsrl    %edi, %eax
+}